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Livestock systems based on subtropical and tropical pastures are characterized by the low productivity of livestock due to the poor nutritional value of the forage (low nitrogen concentration and digestibility, and high fiber and lignin concentrations). These conditions lead to low productivity and, consequently, high absolute emissions of methane (CH4) per unit of product. Dry distilled grains with solubles (DDGS) are the main by-product resulting from ethanol production, and they are characterized by their high-energy fibrous and protein content, thus becoming an option for the supplementation of low-quality forage. This research investigated the effects of dietary DDGS inclusion on dry matter digestibility (DMD) and enteric CH4 emission. Eight adult sheep of 64 ± 8 kg live weight were used. The duration of the study was 54 days, divided into two periods (changeover design), which comprised a 17-day pre-experimental period and 10 days for experimental data collection. Animals were allocated to one of two treatments used: hay (H) as a control treatment, where animals were fed with Rhodes grass hay alone; and H + DDGS, where animals were fed with H supplemented with DDGS. CH4 emissions were estimated using the sulfur hexafluoride (SF6) tracer technique. Diets containing DDGS increased DMI by 22% (p < 0.05) and reduced daily CH4 emissions by 24% (g/d), the CH4 yield by 35% (g/kg DMI), and the average value of CH4 energy per gross energy intake (Ym) by 44%, compared to the control treatment (p < 0.05). The experiment demonstrated that supplementation with DDGS in low-quality roughage reduced daily CH4 emissions, yields, and Ym. View Full-Text Instituto de Patobiología Fil: Gere, José. Universidad Tecnológica Nacional. División Investigación y Desarrollo de Ingenierías; Argentina Fil: Gere, José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Feksa Frasson, Mónica. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; Argentina Fil: Wawrzkiewicz, Marisa. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; Argentina Fil: Fernández Pepi, María Gabriela. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; Argentina Fil: Ramos, María Laura. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; Argentina Fil: Bualo, Ricardo Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina Fil: Ceron Cucchi, Maria Esperanza. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina Fil: Jaurena, Gustavo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; Argentina

The in vitro gas production technique has been used to evaluate forage fermentation kinetics. However, individual and animal species variation can change fermentation patterns due to differences in ruminal environment and microbiota. The aim was to verify whether rumen inoculum (RI) of llama had superior intrinsic digestion capacity and reduced methane (CHDry and organic matter (OM) digestibility produced with llama RI tended to exceed that of sheep (P = 0.099 and 0.074, respectively) at 24 h of incubation. However, at 48 h, the sheep RI presented higher substrate digestibility and asymptotic value of gas production than that of llama (P 0.010). CHLlama RI tended to surpass that of sheep in dry and OM digestibility at 24 h of incubation, but sheep RI at 48 h presented a higher digestibility and gas production value than llama RI. No differences between the two species were detected for CH

It is known that nitrate inhibits ruminal methanogenesis, mainly through competition with hydrogenotrophic methanogens for available hydrogen (H2) and also through toxic effects on the methanogens. However, there is limited knowledge about its effects on the others members of ruminal microbiota and their metabolites. In this study, we investigated the effects of dietary nitrate inclusion on enteric methane (CH4) emission, temporal changes in ruminal microbiota, and fermentation in Holstein calves. Eighteen animals were maintained in individual pens for 45 d. Animals were randomly allocated to either a control (CTR) or nitrate (NIT, containing 15 g of calcium nitrate/kg dry matter) diets. Methane emissions were estimated using the sulfur hexafluoride (SF6) tracer method. Ruminal microbiota changes and ruminal fermentation were evaluated at 0, 4, and 8 h post-feeding. In this study, feed dry matter intake (DMI) did not differ between dietary treatments (P > 0.05). Diets containing NIT reduced CH4 emissions by 27% (g/d) and yield by 21% (g/kg DMI) compared to the CTR (P < 0.05). The pH values and total volatile fatty acids (VFA) concentration did not differ between dietary treatments (P > 0.05) but differed with time, and post-feeding (P < 0.05). Increases in the concentrations of ruminal ammonia nitrogen (NH3–N) and acetate were observed, whereas propionate decreased at 4 h post-feeding with the NIT diet (P < 0.05). Feeding the NIT diet reduced the populations of total bacteria, total methanogens, Ruminococcus albus and Ruminococcus flavefaciens, and the abundance of Succiniclasticum, Coprococcus, Treponema, Shuttlewortia, Succinivibrio, Sharpea, Pseudobutyrivibrio, and Selenomona (P < 0.05); whereas, the population of total fungi, protozoa, Fibrobacter succinogenes, Atopobium and Erysipelotrichaceae L7A_E11 increased (P < 0.05). In conclusion, feeding nitrate reduces enteric CH4 emissions and the methanogens population, whereas it decreases the propionate concentration and the abundance of bacteria involved in the succinate and acrylate pathways. Despite the altered fermentation profile and ruminal microbiota, DMI was not influenced by dietary nitrate. These findings suggest that nitrate has a predominantly direct effect on the reduction of methanogenesis and propionate synthesis. Instituto de Patobiología Fil: Ortiz Chura, Abimael. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina Fil: Ortiz Chura, Abimael. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Gere, José. Universidad Tecnológica Nacional. División Investigación y Desarrollo de Ingenierías; Argentina Fil: Gere, José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Marcoppido, Gisela Ariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina Fil: Marcoppido, Gisela Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Depetris, Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina Fil: Cravero, Silvio Lorenzo Pedro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; Argentina Fil: Cravero, Silvio Lorenzo Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Faverin, Claudia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina Fil: Pinares-Patiño, Cesar. Lincoln University. The Agribusiness Group; Nueva Zelanda Fil: Cataldi, Angel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; Argentina Fil: Cataldi, Angel Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ceron Cucchi, Maria Esperanza. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina Fil: Ceron Cucchi, Maria Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Latin America and Caribbean (LAC) is a developing region characterized for its importance for global food security, producing 23 and 11% of the global beef and milk production, respectively. The region's ruminant livestock sector however, is under scrutiny on environmental grounds due to its large contribution to enteric methane (CH4) emissions and influence on global climate change. Thus, the identification of effective CH4 mitigation strategies which do not compromise animal performance is urgently needed, especially in context of the Sustainable Development Goals (SDG) defined in the Paris Agreement of the United Nations. Therefore, the objectives of the current study were to: 1) collate a database of individual sheep, beef and dairy cattle records from enteric CH4 emission studies conducted in the LAC region, and 2) perform a meta-analysis to identify feasible enteric CH4 mitigation strategies, which do not compromise animal performance. After outlier's removal, 2745 animal records (65% of the original data) from 103 studies were retained (from 2011 to 2021) in the LAC database. Potential mitigation strategies were classified into three main categories (i.e., animal breeding, dietary, and rumen manipulation) and up to three subcategories, totaling 34 evaluated strategies. A random effects model weighted by inverse variance was used (Comprehensive Meta-Analysis V3.3.070). Six strategies decreased at least one enteric CH4 metric and simultaneously increased milk yield (MY; dairy cattle) or average daily gain (ADG; beef cattle and sheep). The breed composition F1 Holstein × Gyr decreased CH4 emission per MY (CH4IMilk) while increasing MY by 99%. Adequate strategies of grazing management under continuous and rotational stocking decreased CH4 emission per ADG (CH4IGain) by 22 and 35%, while increasing ADG by 22 and 71%, respectively. Increased dietary protein concentration, and increased concentrate level through cottonseed meal inclusion, decreased CH4IMilk and CH4IGain by 10 and 20% and increased MY and ADG by 12 and 31%, respectively. Lastly, increased feeding level decreased CH4IGain by 37%, while increasing ADG by 171%. The identified effective mitigation strategies can be adopted by livestock producers according to their specific needs and aid LAC countries in achieving SDG as defined in the Paris Agreement. Fil: Congio, Guilhermo Francklin de Souza. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasil. Corporación Colombiana de Investigación Agropecuaria; Colombia Fil: Bannink, André. University of Agriculture Wageningen; Países Bajos Fil: Mayorga Mogollón, Olga Lucía. Corporación Colombiana de Investigación Agropecuaria; Colombia Fil: Jaurena, Gustavo. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal. Cátedra de Nutrición Animal; Argentina Fil: Gonda, Horacio Leandro. Uppsala Universitet; Suecia Fil: Gere, José Ignacio. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología Veterinaria - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Patobiología Veterinaria; Argentina Fil: Cerón Cucchi, María Esperanza. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina Fil: Ortiz Chura, Abimael. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Tieri, María Paz. Universidad Tecnológica Nacional. Facultad Regional Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación de la Cadena Láctea. - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea; Argentina Fil: Hernandez, Olegario. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-Santiago del Estero; Argentina Fil: Ricci, Patricia. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur. Estacion Experimental Agropecuaria Balcarce. Instituto de Innovación Para la Producción Agropecuaria y El Desarrollo Sostenible. Grupo Vinculado Estacion Experimental Agropecuaria Cuenca del Salado Al Ipads | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Innovación Para la Producción Agropecuaria y El Desarrollo Sostenible. Grupo Vinculado Estacion Experimental Agropecuaria Cuenca del Salado Al Ipads.; Argentina Fil: Juliarena, María Paula. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Lombardi, Banira. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina Fil: Abdalla, Adibe Luiz. Universidade de Sao Paulo; Brasil Fil: Abdalla Filho, Adibe Luiz. Universidade de Sao Paulo; Brasil Fil: Berndt, Alexandre. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Oliveira, Patrícia Perondi Anchão. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Henrique, Fábio Luis. Colegios Asociados de Uberaba; Brasil Fil: Monteiro, Alda Lúcia Gomes. Universidade Federal do Paraná; Brasil Fil: Borges, Luiza Ilha. Universidade Federal do Paraná; Brasil Fil: Ribeiro Filho, Henrique Mendonça Nunes. Universidade Federal de Santa Catarina; Brasil Fil: Ribeiro Pereira, Luiz Gustavo. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Tomich, Thierry Ribeiro. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Campos, Mariana Magalhães. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Machado, Fernanda Samarini. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; Brasil Fil: Marcondes, Marcos Inácio. Universidade Federal de Viçosa.; Brasil Fil: Mercadante, Maria Eugênia Zerlotti. Agencia de Tecnología Agroindustrial de Sao Paulo; Argentina Fil: Sakamoto, Leandro Sannomiya. Agencia de Tecnología Agroindustrial de Sao Paulo; Argentina Fil: Albuquerque, Lucia Galvão. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Carvalho, Paulo César de Faccio. Universidade Federal do Rio Grande do Sul; Brasil Fil: Hristov, Alexander Nikolov. State University of Pennsylvania; Estados Unidos. University of Agriculture Wageningen; Países Bajos. Universidade de Sao Paulo; Brasil. Corporación Colombiana de Investigación Agropecuaria; Colombia

Sulphur (S) dietary excess can limit productive performance and increase polioencephalomalacia (PEM) incidence in feedlot cattle (FC). Sulphur excess ingested is transformed to hydrogen sulphide (H2 S) by sulfo-reducing ruminal bacteria (SRB), being high ruminal H2 S concentration responsible for aforementioned damages. As the ruminal mechanisms involved in H2 S concentrations increase have not been elucidated, this study aimed to evaluate the ruminal environment, and the association between ruminal H2 S and dissimilatory SRB (DSRB) concentration in FC experimentally subjected to S dietary excess. Twelve crossbred steers were randomly assigned to one of two dietary S levels (6 animals per treatment): low (LS, 0.19% S) and high (HS, 0.39% S obtained by sodium sulfate inclusion at 0.86%). The study lasted 38 days, and on days 0, 22 and 38, ruminal gas samples were taken to quantify H2 S concentration, and ruminal fluid to determine total bacteria, DSRB, protozoa, volatile fatty acid and ammonia nitrogen concentration. For ruminal H2 S concentration, S dietary × sampling day interaction was significant (p

Butyrivibrio fibrisolvens forms part of the gastrointestinal microbiome of ruminants and other mammals, including humans. Indeed, it is one of the most common bacteria found in the rumen and plays an important role in ruminal fermentation of polysaccharides, yet, to date, there is no closed reference genome published for this species in any ruminant animal. We successfully assembled the nearly complete genome sequence of B. fibrisolvens strain INBov1 isolated from cow rumen using Illumina paired-end reads, 454 Roche single-end and mate pair sequencing technology. Additionally, we constructed an optical restriction map of this strain to aid in scaffold ordering and positioning, and completed the first genomic structure of this species. Moreover, we identified and assembled the first chromid of this species (pINBov266). The INBov1 genome encodes a large set of genes involved in the cellulolytic process but lacks key genes. This seems to indicate that B. fibrisolvens plays an important role in ruminal cellulolytic processes, but does not have autonomous cellulolytic capacity. When searching for genes involved in the biohydrogenation of unsaturated fatty acids, no linoleate isomerase gene was found in this strain. INBov1 does encode oleate hydratase genes known to participate in the hydrogenation of oleic acids. Furthermore, INBov1 contains an enolase gene, which has been recently determined to participate in the synthesis of conjugated linoleic acids. This work confirms the presence of a novel chromid in B. fibrisolvens and provides a new potential reference genome sequence for this species, providing new insight into its role in biohydrogenation and carbohydrate degradation.

This study was aimed to determine the effect of the rearing system on the establishment and development of different functional groups of microorganisms in the rumen of kid goats. Fifty kids were fed on goat milk until weaning at 45 (TR, traditional rearing system, n = 25) and 30 days of age (alternative rearing system, AR, n = 25). In addition, only AR group was offered with rumen starter from birth. Both groups consumed alfalfa hay and ground corn between 30 and 90 days of age. Five kids from each group were slaughtered at 21, 30, 45, 70 and 90 days old. It was determined the total number of protozoa, anaerobic, amylolytic and cellulolytic bacteria present in the rumen. Kids of AR were lighter in weight than TR kids between 42 and 56 days old. In both rearing systems, anaerobic and amylolytic bacteria were found at 21 days of age, while cellulolytic and protozoa were not found until 45 days of age. Kids of AR had higher quantities of anaerobic and amylolytic bacteria until 30 and 45 days of age, respectively. These results demonstrate the rearing system does not affect the sequence and time in which the functional groups of microorganisms are established in the rumen. However, the alternative rearing system with early intake of solid food allowed the establishment of greater amount of bacteria and protozoa. Nevertheless, the effect of weaning on growth rate was more marked in kids from alternative rearing system, despite its greater microbiological rumen development.

Fil: Grilli, Diego Javier. Facultad de Ciencias Veterinarias y Ambientales, Universidad Juan Agustín Maza, Av. Acceso Este Lateral Sur 2245, CP5519 Mendoza, Argentina. Instituto de Histología y Embriología de Mendoza, Universidad Nacional de Cuyo, Casilla de Correo 56, CP 5500 Mendoza, Argentina. Fil: Mrázek, Jakub. Institute of Animal Physiology and Genetics, Czech Academy of Sciences, v.v.i., Videnska 1083, CP 142 20 Prague, Czech Republic. Fil: Fliegerováb, Kateřina. Institute of Animal Physiology and Genetics, Czech Academy of Sciences, v.v.i., Videnska 1083, CP 142 20 Prague, Czech Republic. Fil: Kopečný, Jan. Institute of Animal Physiology and Genetics, Czech Academy of Sciences, v.v.i., Videnska 1083, CP 142 20 Prague, Czech Republic. Fil: Paez Lama, Sebastian. Instituto Argentino de Investigaciones de las Zonas Áridas, Centro Científico y Tecnológico, M5502BPB Mendoza, Argentina. Fil: Cerón Cucchi, María Esperanza. Instituto de Patobiología. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto Nacional de Tecnología Agropecuaria. De Los Reseros y Dr. Nicolás Repetto S/N, Hurlingham, CP 1686 Buenos Aires, Argentina. Fil: Sosa, Miguel Ángel. Instituto de Histología y Embriología de Mendoza, Universidad Nacional de Cuyo, Casilla de Correo 56, CP 5500 Mendoza, Argentina. Fil: Arenas, Graciela Nora. Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Casilla de Correo 56, CP 5500 Mendoza, Argentina. ARTÍCULO PUBLICADO EN REVISTA EXTERNA. Using culture-independent molecular approaches, we studied the bacterial population changes in the rumen of goats abruptly converted from alfalfa hay to fresh alfalfa diet. Administration of fresh forage with significantly increased soluble nitrogen and soluble protein nitrogen resulted in frothy bloat. Changes of the bacterial composition of rumen were monitored using DGGE analysis of 16S rDNA gene amplicons and quantitative PCR method. As the diet changed, the bacterial population of Bacteroidetes and γ-Proteobacteria decreased, even if animals have not shown signs of frothy bloat. The most severely bloated animals showed an increase of Bacteroidetes phylum. Lactobacillus/Streptococcus group belonging to Firmicutes phylum decreased in response to transferring the animals from hay to a fresh forage-based diet, and did not achieve the values observed at the beginning of the experiment. In summary, changes in the diet and subsequent frothy bloat occurrence produce long-lasting changes in the structure of the microbial community and may be associated with a specific bacterial population belonging to the Bacteroidetes phylum. Sitio de a revista: https://www.sciencedirect.com/science/article/abs/pii/S187114131630172X

The high fibrolytic activity and large biomass of strictly-anaerobic bacteria that inhabit the rumen makes them primarily responsible for the degradation of the forage consumed by ruminants. Llamas feed mainly on low quality fibrous roughages that are digested by an active and diverse microflora. The products of this fermentation are volatile fatty acids and microbial biomass, which will be used by the animals. The aim of this study was to detect the three major fiber-digesting anaerobic bacteria in the forestomach contents of llamas by PCR. In this study, we detected Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes in the forestomach contents of eight native llamas from Argentina. La alta actividad fi brolítica y la gran biomasa de las bacterias anaerobias estrictas que habitan el rumen las hacen las principales responsables de la degradación del forraje consumido por los rumiantes. Las llamas se alimentan sobre todo de forrajes fi brosos de baja calidad, que son digeridos por una activa y diversa microfl ora. Los productos de esta fermentación son ácidos grasos volátiles y biomasa bacteriana, los cuales serán utilizados por el animal. El objetivo de este estudio fue detectar las tres principales bacterias anaerobias que digieren fi bra en el contenido del preestómago de llamas por PCR. En este estudio, detectamos Ruminococcus albus, Ruminococcus fl avefaciens y Fibrobacter succinogenes en el contenido del preestómago de ocho llamas nativas de Argentina. Fil: Cerón Cucchi, María Esperanza. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina Fil: Marcoppido, Gisela Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina Fil: Trangoni, Marcos David. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina Fil: Cravero, Silvio Lorenzo Pedro. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina

This study describes the diversity and concentration of the protozoal population from the forestomach of llamas in Argentina at three altitudinal locations. Protozoal diversity was studied in samples from eight llamas from Hurlingham (Buenos Aires, 43 m altitude), four from Tilcara (Jujuy, 2465 m altitude) and six llamas from Cieneguillas (Jujuy, 3800 m altitude). The total concentrations of protozoa in the forestomach contents were 7.9, 9.1 and 4.1 cells x 10 4 ml -1 in Hurlingham, Tilcara and Cieneguillas, respectively (P>0.05). Entodinium spp. represented 97.9, 92.3 and 71.4% of the protozoal community in Hurlingham, Tilcara and Cieneguillas, respectively, and the remaining protozoa belonged to the Eudiplodinium genus. Entodinium spp. were identified as E. caudatum (mostly morphotype dubardi ), E. longinucleatum , E. parvum, E. bovis , E. exiguum , E. dubardi, and a minor presence of E. bimastus (in three animals) and E. ovibos (in one animal). In regards to the rest of protozoal species, Eudiplodinium maggii is the first reported host record for the genus in llamas. This species was present in the forestomach of 14 out of 18 llamas tested, and in one case it was the unique protozoal species. The vestibuliferids, Dasytricha and Isotricha were absent from the forestomach of llamas. Similarly, other species such as those from the Caloscolex genus, Diplodinium cameli and Entodinium ovumrajae , commonly found in Old World Camelids, were also absent from llamas.